compat/sendmsg.c

   1 /*****************************************************************************
   2  * sendmsg.c: POSIX sendmsg() replacement
   3  *****************************************************************************
   4  * Copyright © 2017 VLC authors and VideoLAN
   5  * Copyright © 2016 Rémi Denis-Courmont
   6  *
   7  * Authors: Rémi Denis-Courmont
   8  *          Dennis Hamester <dhamester@jusst.de>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include <config.h>
  27 #endif
  28
  29 #ifdef _WIN32
  30 # include <errno.h>
  31 # include <stdlib.h>
  32 # include <winsock2.h>
  33
  34 ssize_t sendmsg(int fd, const struct msghdr *msg, int flags)
  35 {
  36     if (msg->msg_controllen != 0)
  37     {
  38         errno = ENOSYS;
  39         return -1;
  40     }
  41
  42     if (msg->msg_iovlen > IOV_MAX)
  43     {
  44         errno = EINVAL;
  45         return -1;
  46     }
  47
  48     WSABUF *buf = malloc(msg->msg_iovlen * sizeof (*buf));
  49     if (buf == NULL)
  50         return -1;
  51
  52     for (unsigned i = 0; i < msg->msg_iovlen; i++)
  53     {
  54         buf[i].len = msg->msg_iov[i].iov_len;
  55         buf[i].buf = (void *)msg->msg_iov[i].iov_base;
  56     }
  57
  58     DWORD sent;
  59
  60     int ret = WSASendTo(fd, buf, msg->msg_iovlen, &sent, flags,
  61                         msg->msg_name, msg->msg_namelen, NULL, NULL);
  62     free(buf);
  63
  64     if (ret == 0)
  65         return sent;
  66
  67     switch (WSAGetLastError())
  68     {
  69         case WSAEWOULDBLOCK:
  70             errno = EAGAIN;
  71             break;
  72     }
  73     return -1;
  74 }
  75
  76 #elif defined __native_client__
  77 #include <errno.h>
  78 #include <limits.h>
  79 #include <stdlib.h>
  80 #include <string.h>
  81 #include <sys/socket.h>
  82 #include <sys/uio.h>
  83
  84 ssize_t sendmsg(int fd, const struct msghdr *msg, int flags)
  85 {
  86     if (msg->msg_controllen != 0)
  87     {
  88         errno = ENOSYS;
  89         return -1;
  90     }
  91
  92     if ((msg->msg_iovlen <= 0) || (msg->msg_iovlen > IOV_MAX))
  93     {
  94         errno = EMSGSIZE;
  95         return -1;
  96     }
  97
  98     size_t full_size = 0;
  99     for (int i = 0; i < msg->msg_iovlen; ++i)
 100         full_size += msg->msg_iov[i].iov_len;
 101
 102     if (full_size > SSIZE_MAX) {
 103         errno = EINVAL;
 104         return -1;
 105     }
 106
 107     /**
 108      * We always allocate here, because whether send/sento allow NULL message or
 109      * not is unspecified.
 110      */
 111     char *data = malloc(full_size ? full_size : 1);
 112     if (!data) {
 113         errno = ENOMEM;
 114         return -1;
 115     }
 116
 117     size_t tmp = 0;
 118     for (int i = 0; i < msg->msg_iovlen; ++i) {
 119         memcpy(data + tmp, msg->msg_iov[i].iov_base, msg->msg_iov[i].iov_len);
 120         tmp += msg->msg_iov[i].iov_len;
 121     }
 122
 123     ssize_t res;
 124     if (msg->msg_name)
 125         res = sendto(fd, data, full_size, flags, msg->msg_name, msg->msg_namelen);
 126     else
 127         res = send(fd, data, full_size, flags);
 128
 129     free(data);
 130     return res;
 131 }
 132
 133 #else
 134 #error sendmsg not implemented on your platform!
 135 #endif